Resistive level sensor for cryo-liquid gas tanks
AssigneeGeneral Motors Corporation
InventorRainer Immel
Life of this patent
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Abstract
The present invention provides a probe having a resistance that varies with temperature and is operable to determine the quantity of a fluid, such as hydrogen, in a storage tank, such as a cryogenic storage tank. The probe relies upon differing heat transfer rates for the gaseous and liquid phases of the fluid and a change in resistance due to a change in temperature of the probe to ascertain the quantity of fluid within the storage tank. The probe can be configured to account for the geometry of the storage tank thereby providing a linearized signal indicative of the quantity of fluid in the storage tank.
Claims20
A level sensor for detecting a quantity of a fluid in a tank, the sensor comprising:
- a resistor having a resistance that varies as a function of a temperature of said resistor, said resistor having a shape that compensates for a varying geometry of the tank, and said resistor includes a wire having a substantially serpentine shape;
- a power source operable to supply at least one of a constant voltage drop across and a constant current to said resistor for a predetermined period;
- and
- a measuring component operable to measure at least one of a current flow through said resistor when supplied with said constant voltage drop and a voltage drop across said resistor when supplied with said constant current during said predetermined period.
A level sensor for detecting a quantity of a fluid in a tank, the sensor comprising:
- a resistor having a resistance that varies as a function of a temperature of said resistor, said resistor having a shape that compensates for a varying geometry of the tank, and said resistor includes a wire having a substantially coil shape;
- a power source operable to supply at least one of a constant voltage drop across and a constant current to said resistor for a predetermined period;
- and
- a measuring component operable to measure at least one of a current flow through said resistor when supplied with said constant voltage drop and a voltage drop across said resistor when supplied with said constant current during said predetermined period.
A method of determining a quantity of a fluid in a tank, the method comprising:
- (a) positioning a generally coil-shaped resistor with a pitch that varies and having a resistance that varies with a temperature of said resistor in the tank and in contact with the fluid, said resistor being oriented so that said varying pitch of said resistor compensates for said geometry of the tank;
- (b) inducing current flow through said resistor during a predetermined period of time;
- (c) measuring a characteristic of said resistor in response to said current flow over said predetermined period of time;
- and
- (d) ascertaining a quantity of the fluid in the tank based on said measured characteristic during said predetermined period of time.
A method of determining a guantity of a fluid in a tank, the method comprising:
- (a) positioning a generally serpentine-shaped resistor with a plurality of segments of varying lengths and having a resistance that varies with a temperature of said resistor in the tank and in contact with the fluid, said resistor being oriented so that said varying lengths of said segments of said resistor compensates for said geometry of the tank;
- (b) inducing current flow through said resistor during a predetermined period of time;
- (c) measuring a characteristic of said resistor in response to said current flow over said predetermined period of time;
- and
- (d) ascertaining a guantity of the fluid in the tank based on said measured characteristic during said predetermined period of time.
A method of determining a quantity of a fluid in a tank, the method comprising:
- (a) positioning a resistor having a resistance that varies with a temperature of said resistor in the tank and in contact with the fluid;
- (b) inducing current flow throuah said resistor during a predetermined period of time;
- (c) measuring a characteristic of said resister in response to said current flow ever said predetermined period of time;
- and
- (d) ascertaining a quantity of the fluid in the tank based on said measured characteristic during said predetermined period of time and compensating for a pressure level in the tank.
Dependencies are inferred from the claim text.